We used to have the technology that'd sort that out. Every file stored in its own compact folder, and would remember the last place the file was played to. Each could be indexed thanks to a handy blank field to write down notes, tracklistings etc. There wasn't any need to convert file formats as there was only the one ubiquitous one. Finding a specific bit of the track could be a bind, and were heavily reliant on batteries, but I think had we persevered with the research it could well have been the dominant audio device today.